11 Sep Steel vs Aluminium, or the best of both?
This is a question that many heavy industry manufacturers ask themselves when embarking on a design and materials analysis for new products. What will perform best to the specifications set either by stringent customer requirements, or to stand out from the competition? Does it need to be durable, lightweight or withstand a harsh climate? TBD has asked these questions in relation to all of our fabricated line, base and ground handling products to ensure the optimum materials are selected, and most of the time it is a well considered combination that makes final production.
In most cases we will robotically weld our chassis and frames from high grade stainless steel. These form the high strength backbone of the stairs, dollies and access platforms for which we are world renowned. We then use aluminium for thicker gauge stairs, handrails and subcomponents to ensure weight is kept to a minimum.
Stainless steel has ‘re-enforced’ its excellent reputation due to its now widespread use in high tech and modern domestic appliances. That said its grade/quality does greatly influence the performance of the material, and that depends on the chromium content (typically 10.5% or higher). Chromium is a hard, corrosion resistant transition element that provides the steel with its primary characteristic of being resilient to rust.
Aluminium is used across all aspects of the aviation industry because of its high performing strength to weight ratio as well as its corrosion resistant layer. Typically, aluminium is not as strong as steel but it makes up for that by being one third of the weight.
These differing beneficial characteristics can be seen across many aspects of usage which we will highlight for you now.
- Thermal Conductivity. Aluminium has a much better thermal conductivity (conductor of heat) than stainless steel. One of the main reasons it is used for heat exchangers and air conditioning units.
- Thermal properties. Stainless can be used at much higher working temperatures than aluminium which can become very soft above about 400 degrees.
- Aluminium is typically cheaper than stainless steel. It is infinitely recyclable, making it one of the most recycled metals in the world. More than 90% of the aluminium used in aviation, automotive and construction applications is recycled, driving a closed-loop circular economy.
- Workability. Aluminium is fairly soft and easier to cut and form. Due to its hardness and resistance to wear and abrasion, stainless can be difficult to work with. It is however much easier to weld using conventional techniques instead of MIG or TIG welding for aluminium.
- Electrical Conductivity. Stainless steel is a really poor conductor compared to most metals therefore it is safer in areas that may be prone to lightning strikes or electrical shorting. Aluminium on the other hand is a very good conductor of electricity.
As such it takes the meticulous review by the TBD Engineering and Design teams to ensure the form, fit and function of our products is well understood prior to choosing the raw materials. This ensures that the actual application of the equipment drives the decision making process at the very beginning of each build.